Photosensitizing properties of water-extractable organic matter from soils.

Water-extractable organic matter (WEOM) was extracted using pure water from two black soils and from the Elliott reference soil of the International Humic Substances Society (IHSS). WEOMs were characterized by chemical and spectroscopic methods. The apparent quantum yields of singlet oxygen, triplet excited states and hydroxyl radicals formation upon irradiation within the wavelength range 290-450 nm were determined using chemical probes and compared to those of standard Elliott humic substances.

Extractability of water-soluble soil organic matter as monitored by spectroscopic and chromatographic analyses.

Purpose: Cold and hot water processes have been intensively used to recover soil organic matter, but the effect of extraction conditions on the composition of the extracts were not well investigated. Our objective was to optimize the extraction conditions (time and temperature) to increase the extracted carbon efficiency while minimizing the possible alteration of water extractable organic matter of soil (WEOM).

Method: WEOM were extracted at 20°C, 60°C, or 80°C for 24 h, 10-60 min, and 20 min, respectively.